Millions of Thanksgiving travelers hit the skies, roads and rails yesterday in what’s expected to be the busiest holiday exodus since 9/11.

The annual turkey-holiday trek got off to a trouble-free start amid beefed-up security at Kennedy, La Guardia and Newark airports as passengers moved swiftly across checkpoints.

“I expected complete chaos and I didn’t see chaos,” said Leni Teaman, 65, who flew out of La Guardia bound for Disney World in Orlando, Fla., with her family. “It looks orderly. I hope it’s as easy as this for everyone else.”

The American Automobile Association said 4.6 million people across the country plan to board planes over the holiday weekend – a 1 percent jump from last year.

Despite the increase, AAA said the number of air travelers is roughly 15 percent below pre-9/11 levels.

The Port Authority estimates 1 million people will fly out of the three area airports for the holiday – a 6.5 percent increase compared to last year.

Passenger flow picked up in the afternoon as people left work early and streamed into La Guardia and onto planes.

“We got here early enough,” said Tracey Haggerty, 32, of Islip, L.I., who arrived three hours early for her flight to Tampa. “There was no line.”

To minimize problems, the federal Transportation Security Administration urged passengers to get to the airport early, store all metal objects in bags and take off coats before going through checkpoints.

“If people follow those simple steps, things will move along,” said TSA spokesman Mark Hatfield. “We have extra screeners at the three airports so we can cut down on long lines.”

Hatfield said travelers don’t mind the heightened security.

“People want to travel safely,” he said.

Despite the increase in air travel, the majority of Americans will take to the road and an estimated 31.1 million people – or 86 percent of all holiday travelers – are expected to pack into cars.